Writer-director David Ayer has described his new film "End of Watch" as akin to "watching YouTube — where something in your mind tells you this is real. This film is like YouTube meets 'Training Day' in a lot of ways." (Ayer wrote "Training Day," which won Denzel Washington an Oscar for his role as a dirty LAPD detective.) So: What does that YouTube comparison mean, exactly?

It means Ayer shoots his movie as if compiled from a mixture of "Cops"-style surveillance footage, shot on "dash-cams" inside the patrol car; video shot by the character played by Jake Gyllenhaal (who, we're told early on, is enrolled in a film class as part of his continuing education); and surreptitious chest-level video. Early on the officers played by Gyllenhaal and Michael Pena affix little spy cams to their uniforms. They're not the only documentarians on the streets of South Central LA.

Key gang-banging adversaries encountered by the cops carry their own cameras and keep nosing in on tense, bloody acts of revenge. Other flashy perspectives come more or less out of nowhere, from no particular perspective, as if Ayer was hired as the unseen tagalong videographer for the latest drive-by. The footage swivels between color and black and white.

It's a full load of self-conscious faux realism for a relatively straightforward outline. Officers Taylor (Gyllenhaal) and Zavala (Pena) are good friends and valiant protectors of the people, though Gyllenhaal's opening voice-over ("I am fate with a badge and gun") indicates that Ayer may forever have one foot in prose and the other in pulp poetry. "End of Watch" proceeds episodically, with Taylor and Zavala crisscrossing paths with an encroaching drug cartel and its street soldiers. Many dead bodies and grisly sights later, amid some fairly effective suspense sequences, we've gotten to know a bit about Zavala's marriage ("I went to prom and got married a week later") and the horn-dog Taylor's romance with the newfound love of his life, played by Anna Kendrick.

Ayer most recently directed the overpacked LAPD drama "Street Kings" (2008), and "End of Watch" is a leaner, more compelling affair. No dirty cops this time, no elaborate conspiracies. Gyllenhaal and Pena are after a lived-in camaraderie and a street-level realism. Pena, especially, succeeds; you buy him every second.

The drawback of the film's visual approach, however, is a considerable one. The relentless first-person shooting in "End of Watch" — figurative and literal — is less about YouTube factuality than it is about Xbox gaming reconfigured for the movies. (It's omnipresent, this approach, and it's not going away: "Dredd 3D" would be nothing without it and, in fact, isn't much with it.) Ayer has talent. He knows how to keep your guts in a knot. For many that'll be enough.

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